A boy and a girl are sitting on the porch.
"I'm a boy," says the child with black hair.
"I'm a girl," says the child with red hair.
If at least one of them is lying, who is which?

What is a word made up of 4 letters, yet is also made up of 3. Sometimes is written with 9 letters, and then with 4. Rarely consists of 6, and never is written with 5.

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?

Find the next number in the series below

21 32 54 87 131 ?

Accidentally, two trains are running in the opposite direction and enter a tunnel that is 200 miles long. A supersonic bird that has fled the lab and taken shelter in the tunnel starts flying from one train towards the other at a speed of 1000 mph. As soon as it reaches the second train, he starts flying back to avoid collision and meets the first train again at the other end. The bird keeps flying to and fro till the trains collide with each other.

What is the total distance that the supersonic bird has traveled till the trains collided?

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?

A man is lying dead in a field where no one is around. His head is split open and his legs are disfigured. Near to him, there is an unopened package. No living organism can be found anywhere at the crime scene.

How did he die?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

Remove two matchsticks to make the below equation correct.

I am never scared but became petrified and can’t live in a house but would die to make one. What am I?